U.S. patent number 7,137,675 [Application Number 10/944,296] was granted by the patent office on 2006-11-21 for road wheel for tracked vehicles.
This patent grant is currently assigned to GS Engineering, Inc.. Invention is credited to Adam C Johnson, Glen R Simula, Steven J Tarnowski.
United States Patent |
7,137,675 |
Simula , et al. |
November 21, 2006 |
Road wheel for tracked vehicles
Abstract
A hollow-shell road wheel for tracked vehicles includes a
generally triangular, outer circumferential cavity formed by an
outer rim and two wall members that extend radially inward at
angles to a generally planar flange at approximately the mid-radius
point of the hollow-shell road wheel. A series of hollow-shell road
wheels assembled in a back-to-back configuration support the
tracked-vehicle and act as guides for the track of the
tracked-vehicle.
Inventors: |
Simula; Glen R (Hancock,
MI), Tarnowski; Steven J (Calumet, MI), Johnson; Adam
C (Houghton, MI) |
Assignee: |
GS Engineering, Inc. (Houghton,
MI)
|
Family
ID: |
37423158 |
Appl.
No.: |
10/944,296 |
Filed: |
September 17, 2004 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
60504531 |
Sep 19, 2003 |
|
|
|
|
Current U.S.
Class: |
305/194;
305/137 |
Current CPC
Class: |
B62D
55/0966 (20130101); B62D 55/14 (20130101); B62D
55/12 (20130101); B33Y 80/00 (20141201) |
Current International
Class: |
B62D
55/12 (20060101); B60B 23/00 (20060101) |
Field of
Search: |
;295/1,7-8,11,21,23,27-28 ;305/136-137,193-197,199
;301/95.102,95.104,95.106,65,63.107,6.91 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
3428196 |
|
Feb 1986 |
|
DE |
|
360974 |
|
Apr 1990 |
|
DE |
|
2020236 |
|
Nov 1979 |
|
GB |
|
Primary Examiner: Bellinger; Jason R.
Attorney, Agent or Firm: Van Dyke, Gardner, Linn &
Burkhart, LLP
Parent Case Text
The present application claims benefit of U.S. provisional
application Ser. No. 60/504,531, filed Sep. 19, 2003, which is
herein incorporated by reference in its entirety.
Claims
What is claimed is:
1. A hollow-shell road wheel for tracked-vehicles comprising: a
peripheral rim member, said peripheral rim member including a first
edge and a second edge; a flange member, said flange member
including a mating surface and an exterior flange surface opposite
said mating surface; a first cavity wall member, said first cavity
wall member being attached to said peripheral rim member at said
first edge; and a second cavity wall member, said second cavity
wall member being attached to said peripheral rim member at said
second edge; said first cavity wall member and said second cavity
wall member being attached to said flange member; said first cavity
wall member, said second cavity wall member, and said peripheral
rim member defining a cavity; wherein said second cavity wall
member and said flange member form a conical section, and wherein a
wear ring is affixed to said first cavity wall member proximate to
said first edge of said peripheral rim member, and wherein said
first cavity wall member and said wear ring have a plurality of
circumferentially located holes adapted to receive a plurality of
fastening elements to secure said wear ring to said first cavity
wall member such that said wear ring is removable and
replaceable.
2. The hollow-shell road wheel of claim 1, wherein said cavity is
triangular in section.
3. The hollow-shell road wheel of claim 1, wherein said first
cavity wall member is angularly attached to said flange member such
that said wear ring is recessed from a plane formed by said mating
surface of said flange member.
4. The hollow-shell road wheel of claim 1, wherein said flange
member is fixed in a plane substantially perpendicular to said
peripheral rim member.
5. The hollow-shell road wheel of claim 1, wherein an elastic
material is fixedly secured to said peripheral rim member.
6. The hollow-shell road wheel of claim 1, wherein said flange
member has a plurality of circumferentially located mounting
holes.
7. The hollow-shell road wheel of claim 1, wherein said flange
member has a center hole.
8. The hollow-shell road wheel of claim 1, wherein said cavity has
a plurality of circumferentially located holes adapted to allow
casting core material to be removed, said holes being located in at
least one of said first cavity wall member, said second cavity wall
member, and said peripheral rim member.
9. The hollow-shell road wheel of claim 1 including at least one
rib in said cavity for strengthening said wheel.
10. The hollow-shell road wheel of claim 1 including metallic foam
within said cavity for strengthening said wheel.
11. The hollow-shell road wheel of claim 1, wherein said wheel is
constructed of a material selected from the group consisting of an
aluminum alloy, magnesium alloy, titanium alloy, plastic, and fiber
reinforced plastic.
12. The hollow-shell road wheel of claim 1, wherein said first
cavity wall member forms an angle of approximately five degrees
with respect to said flange member and said second cavity wall
member forms an angle of approximately forty degrees with respect
to said flange member.
Description
BACKGROUND AND TECHNICAL FIELD OF THE INVENTION
The present invention is directed to wheels for supporting
tracked-vehicles and, in particular, to the road wheels for
tracked-vehicles that provide a rolling interface and support
structure between the track and body of the vehicle.
Tracked-vehicles are a superior means of traversing varied off-road
surfaces compared to vehicles equipped with conventional pneumatic
tires. The tracks provide an increased driving surface and area of
contact with the ground thereby enabling superior support of
heavier vehicles on such varied terrain. In addition, tracks are
more durable than conventional tires such that they are less
susceptible to puncture by sharp or metallic objects.
Tracked-vehicles are utilized in military, forestry, and
construction fields. Military vehicles employing track drive
systems include, for example, the Advanced Amphibious Assault
Vehicle (AAAV), the Bradley Fighting Vehicle, and Abrams tanks.
Generally, the drive systems of such vehicles include a track, a
drive sprocket, a track tensioner, and a series of road wheels that
support the body of the vehicle and serve as a rolling guide
interface to the track.
Existing road wheels for track drive systems on military vehicles
are designed with a single-wall "dish" shape or an "I-beam" shape.
Due to the weight of the tracked vehicles and the environments in
which they are operated, these road wheels are subjected to high
radial and lateral forces. When the vehicle is turning or
traversing a slope at an angle, the lateral forces create
particularly high stresses and strains on the road wheels.
Significantly, as the wall thickness of an existing road wheel is
reduced, the lateral strength decreases exponentially. Therefore,
the high stresses and strains inflicted upon the road wheels
dictate the use of a thicker wall and/or higher strength material
for the existing single-wall shaped road wheels in order to prevent
them from yielding and bending. This, in turn, results in road
wheels of higher weight and/or cost.
The weight of a tracked-vehicle is always a concern, and
particularly so for military vehicles, as weight affects power
needs, fuel consumption, transportability, speed, and mobility of
the vehicle. Further, present military combat situations involve
fewer instances of heavy-duty tank conflicts. Therefore, there is
an increasing need for more lightweight vehicles that are able to
safely transport troops over a wide variety of urban, suburban, and
rural terrains with a moderate level of armament and weaponry. It
is essential that these tracked-vehicles, such as the AAAV and
Bradley, be as light as possible in order to maximize performance
and mobility.
Additionally, as financial resources are always limited regardless
of the application in which the tracked-vehicle is operating, there
is a strong motivation and emphasis to reduce costs without
compromising the safety and ability of such vehicles. As such, road
wheels of relatively high cost are not desired.
Therefore, a road wheel design is needed for track drive systems
for vehicles that provides sufficient lateral and radial strength
without necessitating heavier, thicker walls or costly higher
strength materials.
SUMMARY OF THE INVENTION
In one form of the invention, a hollow-shell road wheel for tracked
vehicles comprises a centrally located and generally flat flange
connected to a circumferential outer cavity. In this form of the
invention, the flange has a center hole for mounting the
hollow-shell road wheel to a hub or suspension arm of a
tracked-vehicle and the outer cavity has a rim at the outermost
circumference of the road wheel.
A hollow-shell road wheel for tracked-vehicles according to another
aspect of the invention includes a circumferential cavity formed by
an outer rim and two wall members that extend radially inward to a
flange at approximately the mid-radius point of the hollow-shell
road wheel. The cavity increases the radial and lateral strength,
enabling use of thinner rim, flange, and wall members, which in
turn reduces the weight of the hollow-shell road wheel. The cavity
also enables use of less costly, lower strength materials without
compromising function of the hollow-shell road wheel.
In a preferred application, two hollow-shell road wheels of the
present invention are mated in a back-to-back configuration and
are, in turn, attached to a hub of a suspension arm of a
tracked-vehicle. A series of hollow-shell road wheel pairs
assembled in such a manner support the tracked-vehicle and act as
guides for the track of the tracked-vehicle.
The cavity design of the hollow-shell road wheel increases its
lateral and radial strength, thereby allowing use of lighter
weight, lower cost alternative materials as compared to traditional
road wheels, while still meeting stress, strain, and safety factor
requirements. Additionally, the cavity design provides a more
durable road wheel for tracked-vehicles. The lower cost, lighter
weight, and increased durability of the hollow-shell road wheel
improves the performance and lowers the cost of tracked-vehicles
utilizing such wheels. Further, the road wheel of the present
invention is self-cleaning because the closed nature of the
circumferential cavity prevents the buildup of mud and debris as
occurs with conventional wheel designs.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side perspective view of a preferred embodiment of two
hollow-shell road wheels of the present invention shown in relation
to the track of a tracked-vehicle;
FIG. 2 is side perspective view of a portion of a tracked vehicle
equipped with hollow-shell road wheels;
FIG. 3 is a rear side perspective view of a preferred embodiment of
a hollow-shell road wheel of the present invention;
FIG. 4 is a sectional side perspective view of the hollow-shell
road wheel of FIG. 3;
FIG. 5 is a rear elevational view of a preferred embodiment of a
hollow-shell road wheel;
FIG. 6 is a front elevational view of the hollow-shell road wheel
of FIG. 5;
FIG. 7 is a side sectional view of the hollow-shell road wheel of
FIG. 5 taken along the line VII--VII;
FIG. 8 is a sectional view of two hollow-shell road wheels mounted
side-by-side on a suspension arm of a tracked-vehicle; and
FIG. 9 is a side sectional view of a portion of the hollow-shell
road wheel of the present invention, including a portion of
metallic foam which may optionally be used in the wheel cavity.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention is embodied in a road wheel for
tracked-vehicles. In particular, the preferred embodiment of the
present invention is intended for the military AAAV vehicle.
However, the invention is readily applicable to the road wheels of
any tracked-vehicle.
A preferred embodiment of the present invention can be seen in
application in FIG. 1 as hollow-shell road wheel assembly 10.
Assembly 10 includes an outwardly mounted, hollow-shell, road wheel
12a affixed to an identical, inwardly mounted, hollow-shell, road
wheel 12b. In FIG. 1, hollow-shell road wheel assembly 10 is shown
in relation to a portion of a track 14 of a tracked-vehicle and
spoked wheel 16, where spoked wheel 16 may be either associated
with a drive sprocket or a track tensioner. On the AAAV, the drive
sprocket is forwardly mounted and the tensioner is rearwardly
mounted. However, on other types of tracked vehicles, the tensioner
may be located in the front and the drive sprocket in the rear. As
seen in FIG. 2, the drive system of a tracked-vehicle 20 includes
drive sprocket 26 and multiple, spaced sets of hollow-shell road
wheel assemblies 10 that are each mounted to individual hubs (not
shown) and suspension arms 22 of the tracked-vehicle 20. The
hollow-shell road wheel assemblies 10 act as rollers for the track
14 and support the tracked-vehicle 20, enabling it to traverse
uneven terrain.
As seen in FIGS. 4 and 7, a preferred embodiment of the
hollow-shell road wheel 12 of the present invention has an outer,
circumferential cavity 30 having a generally triangular shape in
section defined by rim 32, inner wall member 34, and outer wall
member 36. Cavity 30 extends around the entire circumference of
road wheel 12 from approximately the mid-radius 13 of road wheel 12
to its outer periphery. Inner wall member 34 forms an angle 35 of
approximately 5 degrees with respect to flange 38. Outer wall
member 36 forms an angle 37 of approximately 40 degrees with
respect to flange 38. Angle 35 may be varied plus/minus
approximately two degrees to optimize strength, clearance within
guide area 48 (FIG. 8 discussed below), and/or manufacturability.
Angle 37 is dependent upon, and therefore varies with, the width of
track 14, as assembly 10 must be wide enough to provide sufficient
support to track 14.
The cavity 30 design of hollow-shell road wheel 12 increases its
lateral and radial strength such that alternative materials and
manufacturing methods may be used, as compared to traditional road
wheels, while still meeting stress, strain, and safety factor
requirements. Significantly, the alternative materials and
manufacturing methods provide a lighter road wheel, which is
important to the overall performance of the tracked-vehicles 20. In
addition to improving strength, the inclusion of cavity 30 provides
a more durable road wheel; therefore, less maintenance is required
on the tracked-vehicle 20 enabling increased vehicle up-time and
reducing costs. The alternative materials and manufacturing methods
also enable the road wheel to be produced at lower costs relative
to traditional road wheels, thereby improving the overall economic
viability of the tracked-vehicles 20 using the hollow-shell road
wheels 12.
As seen in FIGS. 3 through 7, a hollow-shell road wheel 12 includes
a geoerally planar, radially inner flange 38 that is generally
perpendicular to rim 32. Flange 38 has shaft or suspension arm
receiving hole 40 and hub mounting holes 41 and further includes
mating or rear face 44 and exterior flange surface 46. On a
hollow-shell road wheel assembly 10, as in FIG. 8, the mating or
rear face 44 of flange 38 of the inwardly mounted hollow-shell road
wheel 12b contacts the corresponding mating or rear face or surface
44 of outwardly mounted hollow-shell road wheel 12a. The exterior
flange surface 46 of the inwardly mounted hollow-shell road wheel
12b contacts the hub 53 of a wheel support suspension arm 22 of
tracked-vehicle 20 when the holes 40 are telescoped over a
suspension arm 22. Fasteners 56 such as threaded bolts are then
inserted through the spaced mounting holes 41 of the hollow-shell
road wheel assembly 10 and screwed into the outer face of hub 53
such that assembly 10 is securely affixed to the tracked-vehicle
20. Alternatively, threaded bolts may extend out of hub 53 and lug
nuts may be used to secure assembly 10 to tracked-vehicle 20.
As seen in FIG. 8, hollow-shell road wheel assembly 10 has a
circumferential, generally V-shaped track guide area 48. The track
guide area 48 is created by the angular relation of inner wall
member 34 and flange 38, which forms angle 35 of approximately 5
degrees, on each of the two adjacent hollow-shell road wheels 12a,
12b that are in contact at their respective mating or rear faces
44. When affixed to a tracked-vehicle 20, track guide area 48 rides
over the center guides 17 of track 14, thereby preventing lateral
movement of the track and retaining track 14 on the tracked-vehicle
20. Additionally, as shown in FIG. 9, inner wall member 34 may be
formed with a slightly concave profile to increase the clearance
within track guide area 48.
As seen in FIGS. 5, 7, and 9, hollow-shell road wheel 12 preferably
further includes wear ring 50 adjacent the outer periphery of the
wheel and affixed near the outer edge of inner wall member 34. Wear
ring 50 is recessed from a plane formed by mating or rear face 44
due to angle 35. When hollow-shell road wheels 12 are mounted in
pairs, the wear rings 50 of an assembly 10 contact both sides of
track center guide 17 such that deterioration of the highly
stressed, hollow-shell road wheels 12a and 12b is prevented. Wear
rings 50 may be made from materials such as steel, silicon carbide
composites, titanium composites, or consist of a substrate covered
by a plasma spray wear coating. Other materials with low wear
characteristics may be used as well. As shown in FIG. 5, wear ring
50 and hollow-shell road wheel 12 include wear ring mounting holes
42 receiving threaded or other fasteners 51 such that the annular
wear ring 50 is removable and replaceable. However, in an
alternative embodiment, wear ring 50 may be permanently affixed to
hollow-shell road wheel 12, such as by a welding process, without
altering the function of wear ring 50. In a further alternative
manufacturing method, wear ring 50 can be integrally attached to
inner wall member 34 by insert molding during casting or molding as
is described below.
Hollow-shell road wheel 12 preferably further includes molded
elastomer support surface 52 secured to the circumferential outer
surface of rim 32. Correspondingly, as seen in FIG. 1, each
individual track shoe 18 of track 14 preferably includes two
elastic pads 19, one on either side of center guide 17. The
elastomer support surface 52 of hollow-shell road wheel 12 rolls
over the elastic pads 19 of track 14 when the tracked-vehicle 20 is
in motion. Surface 52 and elastic pads 19 thereby provide a wear
surface, which prevents deterioration of the hollow-shell road
wheel 12 and provides shock absorbency and noise attenuation
characteristics when in use.
The elastomer support surface 52 of hollow-shell road wheel 12 may
be made from elastic materials such as rubber or polyurethane. One
embodiment of the elastomer support surface 52 utilizes rubber of
approximately 70 to 80 Shore A hardness. An alternative embodiment
of the elastomer support surface 52 utilizes polyurethane of
approximately 85 to 98 Shore A hardness. One method of affixing the
elastomer support surface 52 onto the hollow-shell road wheel 12 is
by casting. In this method, an adhesive is applied to rim 32 after
it has been sand blasted. The hollow-shell road wheel 12 is then
inserted into a suitable mold assembly and the hollow-shell road
wheel 12, adhesive, and mold assembly are pre-heated. An
elastomeric material in liquid form is then caused to fill the mold
assembly, thereby bonding to the hollow-shell road wheel 12.
As discussed, the hollow-shell road wheel 12 may be made from
alternative materials relative to traditional road wheels. A
preferred embodiment of the hollow-shell road wheel 12 may be made
from aluminum alloys such as A357, B206, or from the 6000 or 7000
series of alloys. The hollow-shell road wheel 12 may also be made
from magnesium or titanium alloys. The higher the strength of the
alloy that is used, the thinner the rim 32, inner wall member 34,
outer wall member 36, and flange 38 may be made, thereby further
reducing the overall weight of the hollow-shell road wheel 12 while
maintaining the required strength and stiffness.
A preferred embodiment of the hollow-shell road wheel 12 is made by
casting, such as by a semi-permanent mold process or by a lost foam
casting process. In a semi-permanent mold process, cavity 30 is
formed using an internal sand core and the molten alloy is injected
into a mold around the internal sand core. In this method, the
hollow-shell road wheel 12 requires casting material exit holes 54,
as seen in FIGS. 3, 4, and 5, which provide an outlet for removing
the sand after completion of casting. The exit holes 54 may be
located on one of, or some combination of, inner wall member 34,
outer wall member 36, or rim 32. FIG. 5 shows exit holes 54 on
inner wall member 34, and FIG. 4 shows exit holes 54 on both inner
and outer wall members 34, 36, as well as on rim 32. The inclusion
of exit holes 54 on inner wall member 34, outer wall member 36, or
rim 32 affects the strength of hollow-shell road wheel 12, thereby
generally necessitating an increase in the thickness of the
structure including the exit holes 54.
In the lost foam casting process, a hollow-shell road wheel model
is first made out of polystyrene and then dipped into a ceramic
slurry. The coated polystyrene model is placed into a flask or mold
casing that is then filed with sand. When the molten alloy is
introduced to the sand mold, the polystyrene evaporates and the
molten alloy takes the shape of the polystyrene model. In this
process, smaller or fewer exit holes 54 are required.
Alternately, road wheels 12 can be made by other techniques
including laser deposition, selective laser sintering, direct metal
deposition, or other rapid prototyping techniques. These techniques
would allow production of a road wheel 12 including a hollow cavity
30 of essentially the same structure described above but without
core or exit holes such as those shown at 54. Further, these
production methods could allow the inclusion of ribs within cavity
30 such as those shown at 58 in FIG. 6 for further weight
optimization of the structure using such fabrication methods. Ribs
58 can be of either the sprocket type or truss type. If sprocket
type ribs are used, they would extend radially within cavity 30
from the inside surface of inner wall member 34 to the inside
surface of outer wall member 36. If truss type ribs are included,
they would extend radially within cavity 30 from the inner surface
of inner wall member 34 to the inner surface of outer wall member
36 and also engage the inner surface of rim 32 to form a
continuous, triangular brace or truss within the cavity. Inclusion
of ribs 58 as described above would allow the use of thinner inner
wall members 34, outer wall members 36 and rims 32 while
maintaining strength for wheel 12.
Alternately, road wheels 12 can also be manufactured by centrifugal
casting techniques, which would still require a core to produce
cavity 30. In addition to sand type cores, metallic foams such as
shown partially at 60 in FIG. 9 can also be used as a core
material, where in actual use the metallic foams would fill the
entire cavity 30. Metallic foam 60 would remain within cavity 30
such that exit holes 54 would not be required. However, at least
one support hole would be needed to enable metallic foam 60 to be
positioned such that the material used to construct road wheel 12
could be cast around metallic foam 60. If metallic foams are used
as a core material, they would provide an internal, lightweight
stiffening element for the wheel, along with vibration dampening
and/or energy absorption. Use of the metallic foams is an alternate
technique for further reducing the weight of the wheel since the
use of metallic foams as a core material would allow the use of
thinner wall members 34, 36 and a thinner rim 32.
Yet further alternative production methods for road wheel 12 may be
utilized for lightweight vehicles using tracks 14 such as those
described above. In such designs, wheels 12 could be cast using
plastic materials such as Nylon 66 or fiber reinforced plastic
materials such as glass, Kevlar or graphite fiber reinforced
polyester resin.
The combination of material and manufacturing method utilized to
make the hollow-shell road wheel 12 is dependent on various
parameters, as is readily apparent to one of ordinary skill in the
art. The parameters considered include the intended production
volumes, corrosion resistance of the material, desired wall
thickness, and micro-structure of the road wheel as there are
casting risks involved with thinner walls.
The design of the hollow-shell road wheel 12 including a
circumferentially outer cavity 30 and a radially inner generally
planar flange 38 creates a road wheel of generally equivalent
radial and lateral strength of existing single walled road wheels
while having thinner walls and being made of lower strength alloys.
In addition, the design including cavity 30 improves the durability
of the hollow-shell road wheel 12. The reduced weight of the
hollow-shell road wheel 12 enhances the performance of the
tracked-vehicle 20. The ability to utilize lower strength, and less
costly, alloys without sacrificing strength improves the economic
viability of the tracked-vehicle 20.
The above is a description of the preferred embodiments. One
skilled in the art will recognize that changes and modifications
may be made without departing from the spirit of the disclosed
invention, the scope of which is to be determined by the claims
which follow and the breadth of interpretation that the law
allows.
* * * * *